(a) Field of the Invention
The present invention is related to a metallic reflector manufacturing method for an LED package. More particularly, the present invention relates to a metallic reflector manufacturing method for an LED package that the manufacturing process is very simple and the cost is cheap.
(b) Description of the Related Art
Generally, an LED (Light Emitting Diode) is an element that an electron meets hole to emit light in a P-N semiconductor junction, and the LED uses low voltage and current to enable continuous light emitting and has many merits such as low power consumption compared to other light source.
The LED is manufactured to have a general package structure, as shown in FIG. 1, the manufactured LED package 1 includes a first lid frame 12 and a second lid frame 13, and a package body 11 that is integrally formed with the first and the second lid frame 12 and 13.
Also, the package body 11 has an opening 15 that respectively exposes the first and the second lid frame 12 and 13, and an LED chip 14 is disposed on a bottom surface of the opening 15. An encapsulant 16 is charged in the opening 15 to close and seal the opening 15.
And, the LED chip 14 is bonded on the first lid frame 12 through conductive adhesive and is connected to the second lid frame 13 through a bonding wire (W). An inner wall 111 of the opening 15 has a predetermined slant surface such that the light emitted from the LED chip 14 is reflected to the outside.
However, because the inner wall 111 of the opening 15 includes a synthetic resin such as PPA, the color thereof is changed by the light and the heat that are emitted from the LED chip 14, the reflection rate is deteriorated, and therefore it is hard to realize desirable light efficiency.
A metallic reflector surrounding the LED chip is mounted on a substrate so as to resolve the problem such that the color change problem and the reflection deterioration that is caused by the heat and the light of the LED chip are improved by a Korean Patent Laid-Open Publication No. 10-2009-0103292.
A plane figure of the improved ‘LED package’ is shown in FIG. 2 and a sectional view that is cut along a line I-I of FIG. 2 is shown in FIG. 3.
Referring to FIG. 2 and to FIG. 3, the LED package 2 includes a substrate 21, and the substrate 21 has a pair of electrode pattern 22 and 23, and an LED chip 24 is disposed on an upper surface of the substrate 21.
Also, the LED chip 24 is connected to the other side electrode pattern 23 through a bonding wire (W) and is electrically connected to the pair of the electrode pattern 22 and 23.
And, the reflector is made of, for example, ring shape metallic material that is bonded by on the substrate 21 by adhesive.
A bottom surface of the reflector 28 can be bonded to the pair of electrode pattern 22 and 23 by insulation adhesive, and the inner wall of the reflector 28 has a predetermined slant surface to reflect the light that is emitted from the LED chip 24 to the outside.
And, a reflection layer 282 that is coated by a metal is formed on the inner wall 281, and the reflection layer 282 is formed by, for example, aluminization.
Also, an encapsulant 26 of light penetration type resin, for example, silicone resin, or epoxy resin is charged in the reflector 28 to close and seal the LED chip 24 that is disposed on the substrate 21.
The reflector 28 of metallic material that is applied to the LED package improves the color change problem and the reflection rate that are caused by the light and the heat of the LED chip 24.
However, when the reflection layer 282 of the metallic reflector 28 is formed by aluminization, the aluminization is direct performed on the metallic surface, and therefore the reflection layer 282 is lifted such that the reflection performance is deteriorated and the product quality is ruined.
Also, when a conventional reflector 28 is bonded on a substrate 21 by insulation adhesive, the adherence force is deteriorated by narrow area that the reflector 28 is bonded to the substrate 21 and the durability of the LED package is also deteriorated.
And, when the reflector 28 is combined by a screw, because the reflector 28 size is small, there is a problem that a screw cutting for the reflector 28 and the substrate is not easy.
An exemplary embodiment of a ‘molding type LED package’ that a reflector is molded by resin molding material to fix the reflector is shown in FIG. 4.
Referring to FIG. 4, a molding type LED package 1a includes a housing 10 that is formed by molding, for example, PPA resin, lid frame 22a and 24a having plurality of lids, an encapsulant 30 of light penetrating type that epoxy, silicone, or the mixture thereof is used to charge a cavity 12 space that an LED chip (not shown) is housed, and a reflector 40 that is made of metallic material and a reflection portion 42 and a heat radiating portion 44 are integrally formed.
A metallic reflector 40 having a heat radiating portion 44 is disposed on the said molding type LED package, and the heating radiating problem is resolved and simultaneously the reflector 40 can be fixed on the lid frame 22a and 24a. 
However, because the reflector 40 is sealed by the housing 10 and the encapsulant 30, it is yet hard to radiate heat to the outside such that the performance, the durability, and the reliability of the LED package 1 are deteriorated.
And, a plating layer that is plated on a reflection surface of the reflection portion 42 can be lifted by high temperature heat.
Also, the metallic reflector 28 and 40 are manufactured by a die casting forming.
More specifically, first, for example, Zn material for making the reflector 28 and 40 are prepared, and the prepared material is melted in a melting furnace.
Thereafter, the melted material is injected into a die at high pressure, the forming is completed, the reflector product is drawn from the die casting mold, and a trimming process is performed.
The entire of the reflector product or the inner wall 281 and the reflection portion 42 is plated, and the plating process is performed as follows.
Firstly, foreign material or oil is eliminated from the reflector product that is formed by the conventional die casting forming, barrel polishing, chemical polishing, and Ag plating are sequentially performed, and oxidation prevention treatment is performed.
There is a merit that can manufacture complicated product in a die casting forming for the conventional metallic reflector 28 and 40.
However, the die casting forming needs an expensive facility due to metallic melted material, and also there is a problem that the die casting mold price is expensive.
And, because specific metal material that the melding point is low such as Mg, Zn, or Al can be applied to the die casting forming, a kind of metal is limited in manufacturing the metallic reflector.
Also, overall manufacturing process such as metal melting, and trimming process is difficult due to the die casting forming, and barrel polishing and chemical polishing have to be performed after the die casting forming.
And, because the conventional reflector is manufactured by the die casting forming, nonferrous metals such as Zn that the melting point is low has to be used, and therefore raw material cost is high, the process has to be mass production product, and there is a problem that the post processing is not easy.
Also, because the product that is manufactured by the die casting forming, the inside constitution of the metal is weak and there is a problem that the product is weak from the high temperature or an impact.
The above information disclosed in this background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.